Methane conversion apparatus and process using a supersonic flow reactor

ABSTRACT

Apparatus and methods are provided for converting methane in a feed stream to acetylene. A hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation-In-Part of copending application Ser.No. 13/967,391 filed Aug. 15, 2013, which application claims priorityfrom Provisional Application No.

61/691,321 filed Aug. 21, 2012, now expired, the contents of which citedapplications are hereby incorporated by reference in their entirety.

FIELD

Apparatus and methods are disclosed for converting methane in ahydrocarbon stream to acetylene using a supersonic flow reactor.

BACKGROUND

Light olefin materials, including ethylene and propylene, represent alarge portion of the worldwide demand in the petrochemical industry.Light olefins are used in the production of numerous chemical productsvia polymerization, oligomerization, alkylation and other well-knownchemical reactions. These light olefins are essential building blocksfor the modern petrochemical and chemical industries. Producing largequantities of light olefin material in an economical manner, therefore,is a focus in the petrochemical industry. The main source for thesematerials in present day refining is the steam cracking of petroleumfeeds.

The cracking of hydrocarbons brought about by heating a feedstockmaterial in a furnace has long been used to produce useful products,including for example, olefin products.

For example, ethylene, which is among the more important products in thechemical industry, can be produced by the pyrolysis of feedstocksranging from light paraffins, such as ethane and propane, to heavierfractions such as naphtha. Typically, the lighter feedstocks producehigher ethylene yields (50-55% for ethane compared to 25-30% fornaphtha); however, the cost of the feedstock is more likely to determinewhich is used. Historically, naphtha cracking has provided the largestsource of ethylene, followed by ethane and propane pyrolysis, cracking,or dehydrogenation. Due to the large demand for ethylene and other lightolefinic materials, however, the cost of these traditional feeds hassteadily increased.

Energy consumption is another cost factor impacting the pyrolyticproduction of chemical products from various feedstocks. Over the pastseveral decades, there have been significant improvements in theefficiency of the pyrolysis process that have reduced the costs ofproduction. In a typical or conventional pyrolysis plant, a feedstockpasses through a plurality of heat exchanger tubes where it is heatedexternally to a pyrolysis temperature by the combustion products of fueloil or natural gas and air. One of the more important steps taken tominimize production costs has been the reduction of the residence timefor a feedstock in the heat exchanger tubes of a pyrolysis furnace.Reduction of the residence time increases the yield of the desiredproduct while reducing the production of heavier by-products that tendto foul the pyrolysis tube walls. However, there is little room left toimprove the residence times or overall energy consumption in traditionalpyrolysis processes.

More recent attempts to decrease light olefin production costs includeutilizing alternative processes and/or feed streams. In one approach,hydrocarbon oxygenates and more specifically methanol or dimethylether(DME) are used as an alternative feedstock for producing light olefinproducts. Oxygenates can be produced from available materials such ascoal, natural gas, recycled plastics, various carbon waste streams fromindustry and various products and by-products from the agriculturalindustry. Making methanol and other oxygenates from these types of rawmaterials is well established and typically includes one or moregenerally known processes such as the manufacture of synthesis gas usinga nickel or cobalt catalyst in a steam reforming step followed by amethanol synthesis step at relatively high pressure using a copper-basedcatalyst.

Once the oxygenates are formed, the process includes catalyticallyconverting the oxygenates, such as methanol, into the desired lightolefin products in an oxygenate to olefin (OTO) process. Techniques forconverting oxygenates, such as methanol to light olefins (MTO), aredescribed in U.S. Pat. No. 4,387,263, which discloses a process thatutilizes a catalytic conversion zone containing a zeolitic typecatalyst. U.S. Pat. No. 4,587,373 discloses using a zeolitic catalystlike ZSM-5 for purposes of making light olefins. U.S. Pat. No.5,095,163; U.S. Pat. No. 5,126,308 and U.S. Pat. No. 5,191,141 on theother hand, disclose an MTO conversion technology utilizing anon-zeolitic molecular sieve catalytic material, such as a metalaluminophosphate (ELAPO) molecular sieve. OTO and MTO processes, whileuseful, utilize an indirect process for forming a desired hydrocarbonproduct by first converting a feed to an oxygenate and subsequentlyconverting the oxygenate to the hydrocarbon product. This indirect routeof production is often associated with energy and cost penalties, oftenreducing the advantage gained by using a less expensive feed material.

Recently, attempts have been made to use pyrolysis to convert naturalgas to ethylene. U.S. Pat. No. 7,183,451 discloses heating natural gasto a temperature at which a fraction is converted to hydrogen and ahydrocarbon product such as acetylene or ethylene. The product stream isthen quenched to stop further reaction and subsequently reacted in thepresence of a catalyst to form liquids to be transported. The liquidsultimately produced include naphtha, gasoline, or diesel.

While this method may be effective for converting a portion of naturalgas to acetylene or ethylene, it is estimated that this approach willprovide only about a 40% yield of acetylene from a methane feed stream.While it has been identified that higher temperatures in conjunctionwith short residence times can increase the yield, technical limitationsprevent further improvement to this process in this regard.

While the foregoing traditional pyrolysis systems provide solutions forconverting ethane and propane into other useful hydrocarbon products,they have proven either ineffective or uneconomical for convertingmethane into these other products, such as, for example ethylene. WhileMTO technology is promising, these processes can be expensive due to theindirect approach of forming the desired product. Due to continuedincreases in the price of feeds for traditional processes, such asethane and naphtha, and the abundant supply and corresponding low costof natural gas and other methane sources available, for example the morerecent accessibility of shale gas, it is desirable to providecommercially feasible and cost effective ways to use methane as a feedfor producing ethylene and other useful hydrocarbons.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view of a supersonic reactor inaccordance with various embodiments described herein;

FIG. 2 is a schematic view of a system for converting methane intoacetylene and other hydrocarbon products in accordance with variousembodiments described herein;

FIG. 3 is a partial side cross-sectional view showing portions of thesupersonic reactor of FIG. 1 in accordance with various embodimentsdescribed herein;

FIG. 4 is a partial side cross-sectional view showing portions of thesupersonic reactor of FIG. 1 in accordance with various embodimentsdescribed herein;

FIG. 5 is a cross-sectional view showing a supersonic reactor inaccordance with various embodiments described herein;

FIG. 6 is a partial side cross-sectional view showing portions of thesupersonic reactor of FIG. 1 in accordance with various embodimentsdescribed herein;

FIG. 7 is a partial side cross-sectional view showing portions of thesupersonic reactor of FIG. 1 in accordance with various embodimentsdescribed herein;

FIG. 8 is a partial side cross-sectional view showing portions of thesupersonic reactor of FIG. 1 in accordance with various embodimentsdescribed herein;

FIG. 9 is a perspective view of a portion of the supersonic reactor ofFIG. 1;

FIG. 10 is a partial side cross-sectional view showing portions of thesupersonic reactor of FIG. 1 in accordance with various embodimentsdescribed herein;

FIG. 11 is a partial side cross-sectional view showing portions of thesupersonic reactor of FIG. 1 in accordance with various embodimentsdescribed herein;

FIG. 12 is a partial side cross-sectional view showing portions of thesupersonic reactor of FIG. 1 in accordance with various embodimentsdescribed herein;

FIG. 13 is a perspective cut-away view showing portions of thesupersonic reactor of FIG. 1 in accordance with various embodimentsdescribed herein;

FIG. 14 is a schematic view of a supersonic reactor in accordance withvarious embodiments described herein.

DETAILED DESCRIPTION

One proposed alternative to the previous methods of producing olefinsthat has not gained much commercial traction includes passing ahydrocarbon feedstock into a supersonic reactor and accelerating it tosupersonic speed to provide kinetic energy that can be transformed intoheat to enable an endothermic pyrolysis reaction to occur. Variations ofthis process are set out in U.S. Pat. No. 4,136,015; U.S. Pat. No.4,724,272; and Russian Patent No. SU 392723A. These processes includecombusting a feedstock or carrier fluid in an oxygen-rich environment toincrease the temperature of the feed and accelerate the feed tosupersonic speeds. A shock wave is created within the reactor toinitiate pyrolysis or cracking of the feed.

More recently, U.S. Pat. No. 5,219,530 and U.S. Pat. No. 5,300,216 havesuggested a similar process that utilizes a shock wave reactor toprovide kinetic energy for initiating pyrolysis of natural gas toproduce acetylene. More particularly, this process includes passingsteam through a heater section to become superheated and accelerated toa nearly supersonic speed. The heated fluid is conveyed to a nozzlewhich acts to expand the carrier fluid to a supersonic speed and lowertemperature. An ethane feedstock is passed through a compressor andheater and injected by nozzles to mix with the supersonic carrier fluidto turbulently mix together at a speed of about Mach 2.8 and atemperature of about 427° C. The temperature in the mixing sectionremains low enough to restrict premature pyrolysis. The shockwavereactor includes a pyrolysis section with a gradually increasingcross-sectional area where a standing shock wave is formed by backpressure in the reactor due to flow restriction at the outlet. The shockwave rapidly decreases the speed of the fluid, correspondingly rapidlyincreasing the temperature of the mixture by converting the kineticenergy into heat. This immediately initiates pyrolysis of the ethanefeedstock to convert it to other products. A quench heat exchanger thenreceives the pyrolized mixture to quench the pyrolysis reaction.

Methods and apparatus for converting hydrocarbon components in methanefeed streams using a supersonic reactor are generally disclosed. As usedherein, the term “methane feed stream” includes any feed streamcomprising methane. The methane feed streams provided for processing inthe supersonic reactor generally include methane and form at least aportion of a process stream. The apparatus and methods presented hereinconvert at least a portion of the methane to a desired producthydrocarbon compound to produce a product stream having a higherconcentration of the product hydrocarbon compound relative to the feedstream.

The term “hydrocarbon stream” as used herein refers to one or morestreams that provide at least a portion of the methane feed streamentering the supersonic reactor as described herein or are produced fromthe supersonic reactor from the methane feed stream, regardless ofwhether further treatment or processing is conducted on such hydrocarbonstream. With reference to the example illustrated in FIG. 2, the“hydrocarbon stream” may include the methane feed stream 1, a supersonicreactor effluent stream 2, a desired product stream 3 exiting adownstream hydrocarbon conversion process or any intermediate orby-product streams formed during the processes described herein. Thehydrocarbon stream may be carried via a process stream line 115, asshown in FIG. 2, which includes lines for carrying each of the portionsof the process stream described above. The term “process stream” as usedherein includes the “hydrocarbon stream” as described above, as well asit may include a carrier fluid stream, a fuel stream 4, an oxygen sourcestream 6, or any streams used in the systems and the processes describedherein. The process stream may be carried via a process stream line 115,which includes lines for carrying each of the portions of the processstream described above. As illustrated in FIG. 2, any of methane feedstream 1, fuel stream 4, and oxygen source stream 6, may be preheated,for example, by one or more heaters 7.

Prior attempts to convert light paraffin or alkane feed streams,including ethane and propane feed streams, to other hydrocarbons usingsupersonic flow reactors have shown promise in providing higher yieldsof desired products from a particular feed stream than other moretraditional pyrolysis systems. Specifically, the ability of these typesof processes to provide very high reaction temperatures with very shortassociated residence times offers significant improvement overtraditional pyrolysis processes. It has more recently been realized thatthese processes may also be able to convert methane to acetylene andother useful hydrocarbons, whereas more traditional pyrolysis processeswere incapable or inefficient for such conversions.

The majority of previous work with supersonic reactor systems, however,has been theoretical or research based, and thus has not addressedproblems associated with practicing the process on a commercial scale.In addition, many of these prior disclosures do not contemplate usingsupersonic reactors to effectuate pyrolysis of a methane feed stream,and tend to focus primarily on the pyrolysis of ethane and propane. Oneproblem that has recently been identified with adopting the use of asupersonic flow reactor for light alkane pyrolysis, and morespecifically the pyrolysis of methane feeds to form acetylene and otheruseful products therefrom, includes the damaging effects that the severeoperating conditions for pyrolysis of the methane can have on thesupersonic flow reactor and other associated equipment. Previous workhas not fully appreciated or addressed these severe operatingconditions. For example, the supersonic reactor may operate attemperatures up to 3000° C. or higher, along with high pressures. Thesehigh temperatures and pressures pose a risk for mechanical failurewithin reactor walls of the reactor as a result of melting, rupture, orcreep. Specifically, at elevated temperature, it has been identifiedthat hot spots on the walls may indicate shell melting. In addition,even where the walls are cooled, chemically based damage may occur, suchas, for example redox reactions forming non-passive products that arelost to the gas flow, causing recession. Further, translated oxidationmay occur, creating non-adhering oxides that are lost to the gas flow.

In addition, a carrier stream and feed stream may travel through thereactor at supersonic speeds, which can quickly erode many materialsthat could be used to form the reactor shell. Moreover, certainsubstances and contaminants that may be present in the hydrocarbonstream can cause corrosion, oxidation, and/or reduction of the reactorwalls or shell and other equipment or components of the reactor. Suchcomponents causing corrosion, oxidation, or reduction problems mayinclude, for example hydrogen sulfide, water, methanethiol, arsine,mercury vapor, carbidization via reaction within the fuel itself, orhydrogen embrittlement. Another problem that may be present at hightemperatures is reaction with transient species, such as radicals, e.g.hydroxide.

In accordance with various embodiments disclosed herein, therefore,apparatus and methods for converting methane in hydrocarbon streams toacetylene and other products are provided. Apparatus in accordanceherewith, and the use thereof, have been identified to improve theoverall process for the pyrolysis of light alkane feeds, includingmethane feeds, to acetylene and other useful products. The apparatus andprocesses described herein also improve the ability of the apparatus andassociated components and equipment thereof to withstand degradation andpossible failure due to extreme operating conditions within the reactor.

In accordance with one approach, the apparatus and methods disclosedherein are used to treat a hydrocarbon process stream to convert atleast a portion of methane in the hydrocarbon process stream toacetylene. The hydrocarbon process stream described herein includes themethane feed stream provided to the system, which includes methane andmay also include ethane or propane. The methane feed stream may alsoinclude combinations of methane, ethane, and propane at variousconcentrations and may also include other hydrocarbon compounds as wellas contaminants. In one approach, the hydrocarbon feed stream includesnatural gas. The natural gas may be provided from a variety of sourcesincluding, but not limited to, gas fields, oil fields, coal fields,fracking of shale fields, biomass, and landfill gas. In anotherapproach, the methane feed stream can include a stream from anotherportion of a refinery or processing plant. For example, light alkanes,including methane, are often separated during processing of crude oilinto various products and a methane feed stream may be provided from oneof these sources. These streams may be provided from the same refineryor different refinery or from a refinery off gas. The methane feedstream may include a stream from combinations of different sources aswell.

In accordance with the processes and systems described herein, a methanefeed stream may be provided from a remote location or at the location orlocations of the systems and methods described herein. For example,while the methane feed stream source may be located at the same refineryor processing plant where the processes and systems are carried out,such as from production from another on-site hydrocarbon conversionprocess or a local natural gas field, the methane feed stream may beprovided from a remote source via pipelines or other transportationmethods. For example a feed stream may be provided from a remotehydrocarbon processing plant or refinery or a remote natural gas field,and provided as a feed to the systems and processes described herein.Initial processing of a methane stream may occur at the remote source toremove certain contaminants from the methane feed stream. Where suchinitial processing occurs, it may be considered part of the systems andprocesses described herein, or it may occur upstream of the systems andprocesses described herein. Thus, the methane feed stream provided forthe systems and processes described herein may have varying levels ofcontaminants depending on whether initial processing occurs upstreamthereof.

In one example, the methane feed stream has a methane content rangingfrom about 65 mol-% to about 100 mol-%. In another example, theconcentration of methane in the hydrocarbon feed ranges from about 80mol-% to about 100 mol-% of the hydrocarbon feed. In yet anotherexample, the concentration of methane ranges from about 90 mol-% toabout 100 mol-% of the hydrocarbon feed.

In one example, the concentration of ethane in the methane feed rangesfrom about 0 mol-% to about 35 mol-% and in another example from about 0mol-% to about 10 mol-%. In one example, the concentration of propane inthe methane feed ranges from about 0 mol-% to about 5 mol-% and inanother example from about 0 mol-% to about 1 mol-%.

The methane feed stream may also include heavy hydrocarbons, such asaromatics, paraffinic, olefinic, and naphthenic hydrocarbons. Theseheavy hydrocarbons if present will likely be present at concentrationsof between about 0 mol-% and about 100 mol-%. In another example, theymay be present at concentrations of between about 0 mol-% and 10 mol-%and may be present at between about 0 mol-% and 2 mol-%.

The apparatus and method for forming acetylene from the methane feedstream described herein utilizes a supersonic flow reactor forpyrolyzing methane in the feed stream to form acetylene. The supersonicflow reactor may include one or more reactors capable of creating asupersonic flow of a carrier fluid and the methane feed stream andexpanding the carrier fluid to initiate the pyrolysis reaction. In oneapproach, the process may include a supersonic reactor as generallydescribed in U.S. Pat. No. 4,724,272, which is incorporated herein byreference, in its entirety. In another approach, the process and systemmay include a supersonic reactor such as described as a “shock wave”reactor in U.S. Pat. No. 5,219,530 and U.S. Pat. No. 5,300,216, whichare incorporated herein by reference, in their entirety. In yet anotherapproach, the supersonic reactor described as a “shock wave” reactor mayinclude a reactor such as described in “Supersonic Injection and Mixingin the Shock Wave Reactor” Robert G. Cerff, University of WashingtonGraduate School, 2010.

While a variety of supersonic reactors may be used in the presentprocess, an exemplary reactor 5 is illustrated in FIG. 1. Referring toFIG. 1, the supersonic reactor 5 includes a reactor vessel 10 generallydefining a reactor chamber 15. While the reactor 5 is illustrated as asingle reactor, it should be understood that it may be formed modularlyor as separate vessels. If formed modularly or as separate components,the modules or separate components of the reactor may be joined togetherpermanently or temporarily, or may be separate from one another withfluids contained by other means, such as, for example, differentialpressure adjustment between them. A combustion zone or chamber 25 isprovided for combusting a fuel to produce a carrier fluid with thedesired temperature and flowrate. The reactor 5 may optionally include acarrier fluid inlet 20 for introducing a supplemental carrier fluid intothe reactor. One or more fuel injectors 30 are provided for injecting acombustible fuel, for example hydrogen, into the combustion chamber 26.The same or other injectors may be provided for injecting an oxygensource into the combustion chamber 26 to facilitate combustion of thefuel. The fuel and oxygen source injection may be in an axial direction,tangential direction, radial direction, or other direction, including acombination of directions. The fuel and oxygen are combusted to producea hot carrier fluid stream typically having a temperature of from about1200° to about 3500° C. in one example, between about 2000° and about3500° C. in another example, and between about 2500° and about 3200° C.in yet another example. It is also contemplated herein to produce thehot carrier fluid stream by other known methods, includingnon-combustion methods. According to one example the carrier fluidstream has a pressure of about 1 atm or higher, greater than about 2 atmin another example, and greater than about 4 atm in another example.

The hot carrier fluid stream from the combustion zone 25 is passedthrough a supersonic expander 51 that includes a converging-divergingnozzle 50 to accelerate the velocity of the carrier fluid to above aboutMach 1.0 in one example, between about Mach 1.0 and Mach 4.0 in anotherexample, and between about Mach 1.5 and 3.5 in another example. In thisregard, the residence time of the fluid in the reactor portion of thesupersonic flow reactor is between about 0.5 and 100 ms in one example,about 1.0 and 50 ms in another example, and about 1.5 and 20 ms inanother example. The temperature of the carrier fluid stream through thesupersonic expander by one example is between about 1000° C. and about3500° C., between about 1200° C. and about 2500° C. in another example,and between about 1200° C. and about 2000° C. in another example.

A feedstock inlet 40 is provided for injecting the methane feed streaminto the reactor 5 to mix with the carrier fluid. The feedstock inlet 40may include one or more injectors 45 for injecting the feedstock intothe nozzle 50, a mixing zone 55, a diffuser zone 60, or a reaction zoneor chamber 65. The injector 45 may include a manifold, including forexample a plurality of injection ports or nozzles for injecting the feedinto the reactor 5.

In one approach, the reactor 5 may include a mixing zone 55 for mixingof the carrier fluid and the feed stream. In one approach, asillustrated in FIG. 1, the reactor 5 may have a separate mixing zone,between for example the supersonic expander 51 and the diffuser zone 60,while in another approach, the mixing zone is integrated into thediffuser section, and mixing may occur in the nozzle 50, expansion zone60, or reaction zone 65 of the reactor 5. An expansion zone 60 includesa diverging wall 70 to produce a rapid reduction in the velocity of thegases flowing therethrough, to convert the kinetic energy of the flowingfluid to thermal energy to further heat the stream to cause pyrolysis ofthe methane in the feed, which may occur in the expansion section 60and/or a downstream reaction section 65 of the reactor. The fluid isquickly quenched in a quench zone 72 to stop the pyrolysis reaction fromfurther conversion of the desired acetylene product to other compounds.Spray bars 75 may be used to introduce a quenching fluid, for examplewater or steam into the quench zone 72.

The reactor effluent exits the reactor via outlet 80 and as mentionedabove forms a portion of the hydrocarbon stream. The effluent willinclude a larger concentration of acetylene than the feed stream and areduced concentration of methane relative to the feed stream. Thereactor effluent stream may also be referred to herein as an acetylenestream as it includes an increased concentration of acetylene. Theacetylene stream may be an intermediate stream in a process to formanother hydrocarbon product or it may be further processed and capturedas an acetylene product stream. In one example, the reactor effluentstream has an acetylene concentration prior to the addition of quenchingfluid ranging from about 2 mol-% to about 30 mol-%. In another example,the concentration of acetylene ranges from about 5 mol-% to about 25mol-% and from about 8 mol-% to about 23 mol-% in another example.

The reactor vessel 10 includes a reactor shell 11. It should be notedthat the term “reactor shell” refers to the wall or walls forming thereactor vessel, which defines the reactor chamber 15. The reactor shell11 will typically be an annular structure defining a generally hollowcentral reactor chamber 15. The reactor shell 11 may include a singlelayer of material, a single composite structure or multiple shells withone or more shells positioned within one or more other shells. Thereactor shell 11 also includes various zones, components, and ormodules, as described above and further described below for thedifferent zones, components, and or modules of the supersonic reactor 5.The reactor shell 11 may be formed as a single piece defining all of thevarious reactor zones and components or it may be modular, withdifferent modules defining the different reactor zones and/orcomponents.

By one approach, one or more portions of the reactor wall or shell 11are formed as a casting. In this regard, the one or more portions maynot be formed by welding or forming or other manufacturing methods,although additional treating may be performed on the casting asdescribed below. Without intending to be bound by theory, it is believedthat because welds often include residual stress, forming the reactorwall or walls by welding may yield a reactor that is more susceptible tofailure or rupture under high temperatures and pressures. In addition,due to their varying microstructure and possible composition gradients,welds may also be more susceptible to corrosion and cracking. Similarly,it is believed that forming the reactor walls would result innon-negligible residual stresses formed in the reactor walls, causingsimilar problems with operation at high temperatures and pressures.Thus, by forming a portion of the reactor shell as a casting, a moreisotropic microstructure is provided. The cast portion of the reactorshell may provide corrosion resistance over similar components formed byother methods, such as welding or forming. Forming the reactor shellfrom a casting may also provide more uniform heat flux and more uniformtemperatures in the component. Forming the portion of the reactor shellfrom a casting may also provide better and more uniform high temperaturecreep and failure resistance than forming the shell by other methods.

By one approach, the casting may include a directional casting toprovide improved thermal shock resistance and creep resistance at theelevated reaction temperatures and pressures. In one approach, thecasting includes a columnar grain structure. In another approach, thecasting includes a single crystal structure.

The casting may be formed from one or more materials as describedfurther below. The cast portion of the reactor may be further treated byvarious methods known in the art. For example, the cast reactor shell 11may be coated, as further described herein, heat treated, tempered,carbided, nitride, or treated in other known methods to improve itsproperties.

A single casting may be used to form the entire reactor shell 11, or thereactor shell 11 may include individually cast components or modules, asdescribed further herein, that are assembled to form the reactor shell11. Further, where the reactor shell 11 includes various layers,including coatings, inner and outer shells, etc., as further describedherein, these layers may be cast separately or together, andsubsequently maintained separately or joined together.

According to various other approaches, one or more portions of thesupersonic reactor shell may be formed by known methods other thancasting, such as, for example powder metallurgy, which may be densifiedby hot isostatic pressing, hipping a powder to a substrate, or lasersintering, or other suitable sintering methods, or machining from abillet.

By one approach, at least a portion of the reactor shell 11 isconstructed of a material having a high melting temperature to withstandthe high operating temperatures of the supersonic reactor 5. In oneapproach, one or more materials forming the portion of the reactor shell11 may have a long low-cycle fatigue life, high yield strength,resistance to creep and stress rupture, oxidation resistance, andcompatibility with coolants and fuels. In one example, at least aportion of the reactor shell 11 is formed of a material having a meltingtemperature of between about 1200° and about 4000° C., and in anotherexample from about 1800° to about 3500° C. The materials may alsoexhibit microstructural stability through diverse thermal and mechanicalprocessing procedures, compatibility with bonding processes and goodadherence of oxidation resistant coatings. Some preferred materials forforming at least a portion of the reactor shell include superalloys andnickel and gamma Ti alumindes. By one approach, the superalloy it is anickel based superalloy, and by another approach, the superalloy is aniron based superalloy.

In one approach, the reactor shell 11 or wall portion is formed from asuperalloy. In this regard, the wall may provide excellent mechanicalstrength and creep resistance at combustion and pyrolysis temperaturesoccurring within the reactor. In this manner, the apparatus may alsorestrict melting or failure due to the operating temperature andpressures in the reactor chamber 15.

According to another approach, the portion of the reactor shell 11 isformed from a material selected from the group consisting of a carbide,a nitride, titanium diboride, a sialon ceramic, zirconia, thoria, acarbon-carbon composite, tungsten, tantalum, molybdenum, chromium,nickel and alloys thereof

According to yet another approach, the portion of the reactor shell 11is formed as a casting wherein the casting comprises a componentselected from the group consisting of duplex stainless steel, superduplex stainless steel, and nickel-based high-temperature low creepsuperalloy.

Chromium or nickel may be included to provide good corrosion resistance.

By another aspect, the reactor walls are constructed of a materialhaving high thermal conductivity. In this manner, heat from reactorchamber 15 may be quickly removed therefrom.

This may restrict a skin temperature of an internal surface of thereactor shell 11 from being heated to temperatures at or near thereactor temperature, which may cause melting, chemical fire, or otherdeterioration, to the reactor shell 11 walls. In one example, the one ormore portions of the reactor are formed from a material having a thermalconductivity of between about 200 and about 500 W/m-K. In anotherexample, the thermal conductivity is between about 300 and about 450W/m-K. In yet another example, the thermal conductivity is between about200 and about 346 W/m-K and may be between about 325 and about 375 W/m-Kin yet another example.

It has been found that according to this approach, the reactor shell maybe formed from a material having a relatively low melting temperature aslong as the material has a very high conductivity. Because heat from thereaction chamber 15 is quickly removed in this approach, the reactorshell 11 is not exposed to as high as the temperature. In this regard,by forming the reactor shell portion from a material having a highthermal conductivity, the material may have a melting temperature belowthe temperature in the reactor chamber 15. In one example, the portionof the reactor shell 11 is formed from a material having a meltingtemperature of between about 500° and about 2000° C. In another example,the reactor shell 11 portion may be formed from a material having amelting temperature of between about 800° and about 1300° C. and may beformed from a material having a melting temperature of between about1000° and about 1200° C. in another example.

By one approach, the material having a high thermal conductivityincludes a metal or metal alloy. In one approach, one or more portionsof the reactor shell 11 may be formed from copper, silver, aluminum,zirconium, niobium, and their alloys. In this regard, it should be notedthat one or more of the materials listed above may also be used to forma coating on a reactor shell substrate or to form a layer of amultilayer reactor shell 11. By one approach, the reactor shell 11portion includes copper or a copper alloy. In one example, the reactorshell portion includes a material selected from the group consisting ofcopper chrome, copper chrome zinc, copper chrome niobium, copper nickeland copper nickel tungsten. In another example, the reactor shellportion comprises niobium-silver. In order to enhance the removal ofheat from reactor chamber, cooling may be used to more quickly removethe heat from the reactor chamber so that a temperature thereof ismaintained below and allowable temperature.

By another approach, the reactor shell 11 may include a plurality oflayers. The reactor shell 11 illustrated in FIG. 3 includes an innerlayer 210 defining the reactor chamber 15 and an outer layer 205 formedabout the inner 210. While the reactor shell 11 illustrated in FIG. 3has two layers for ease of explanation, as illustrated in FIG. 8, itshould be understood that the reactor shell 11 may include three or morelayers having one or more intermediate layers 211 between the innerlayer 210 and the outer layer 205. Further, one or more additional outerlayers 212 may be positioned outside of outer layer 212. One or moreadditional inner layers may be positioned inside of inner layer 210.

In one approach, the inner layer 210 includes a coating that is formedon an inner surface of the outer layer 205 or any interveningintermediate layers 211. In this regard, the outer layer 205 forms asubstrate on which the inner layer 210 coating is applied.Alternatively, the inner layers 210 may provide a substrate on which anouter layer 205 coating is applied. One or both of the inner layer 210and the outer layer 205 may be formed as a casting as describedpreviously or formed in other known manners in accordance with thisapproach.

In one approach, at least a portion of the inner layer 210 includes ahigh melting temperature material as described above. According toanother approach, the inner layer 210 includes a material selected fromthe group consisting of a carbide, a nitride, titanium diboride, asialon ceramic, zirconia, thoria, a carbon-carbon composite, tungsten,tantalum, molybdenum, chromium, nickel and alloys thereof. By yetanother approach, the inner layer 210 includes a superalloy, and byanother approach includes a material selected from the group consistingof duplex stainless steel, super duplex stainless steel, andnickel-based high-temperature low creep superalloy. In this regard, theinner layer 210 may be selected to provide beneficial operatingcharacteristics, particularly as it is exposed to the harsh operatingconditions within the reactor chamber 15, including the high temperaturethereof.

In another approach, at least a portion of the inner layer 210 includesa high thermal conductivity material as described above. According toanother approach, the inner layer 210 includes a material selected fromthe group consisting of copper, silver, aluminum, zirconium, niobium,and alloys thereof. By yet another approach, the inner layer 210includes a material selected from the group consisting of copper chrome,copper chrome zinc, copper chrome niobium, copper nickel and coppernickel tungsten. In another example, the reactor shell portion comprisesniobium-silver. In this regard, the inner layer 210 may be selected toprovide beneficial operating characteristics, particularly as it isexposed to the harsh operating conditions within the reactor chamber 15,including the high temperature thereof.

In one approach, the outer layer 205 may be formed of a differentmaterial than the inner layer 210. The outer layer 205 material may beselected to provide structural support or other desirable properties tothe reactor shell 11. In one example, the outer layer 205 or anintermediate layer includes corrosion resistant steel. Other suitablematerials for forming the outer layer 205 of the reactor shell 11include, but are not limited to, duplex stainless steel, super duplexstainless steel, and nickel-based high-temperature low creep superalloy,Nimonic™ nickel-based high-temperature low creep superalloy, Inco™ 718,Haynes™, 230, or other nickel alloys such as Mar-M-247.

In one approach, the inner layer 210 includes a thermal barrier coating.Thermal barrier coatings may be formed from a material that exhibitsdesirable properties for use in the reactor chamber 15 such as, forexample, high melting temperature to withstand the high temperatures inthe reactor chamber 15. For example, the thermal barrier coating mayinclude

Yttria-stabilized zirconia, lanthanum and rare earth-doped lanthanumhexaluminate, hafnium carbide or tungsten, as both materials have highmelting temperatures, good mechanical properties at high operatingtemperatures, and optionally low thermal conductivity.

In one approach, a bond coat is provided between the inner layer 210 andthe surface of the outer layer 205, including the thermal barriercoating by one approach. The bond coat may include, NiCrAlY, NiCoCrAlYalloys that are applied on the metal surface by plasma spray, electronbeam PVD, or other methods known in the art. Other bond coatings forcopper alloys may include NiAl applied by low pressure, vacuum plasmaspray, or other methods known in the art.

The layered reactor shell 11 may be formed in any known manner known inthe art.

In one approach, an internal diameter coating formed on a mandrel may beused to provide a layered reactor shell by providing a coating on asubstrate material. By another approach, a coating may be formed on asubstrate by hot isostatic pressing to provide the layered reactor shell11. By yet another approach, cladding may be used to provide a coatingon a substrate. In still another approach, the inner layer and outerlayers may be separately formed and joined together. An example of thisapproach includes separately casting the inner layer 210 and the outerlayer 205 and brazing them together to form the layered reactor shell11. Bi-casting may also be used by casting a second alloy about a firstalloy.

In another approach, as illustrated in FIG. 4, at least a portion of thereactor shell 11 may include a separate inner shell 215 and outer shell220. Similar to the layered reactor shell 11 described previously, areactor shell having a separate inner shell 215 and outer shell 220 mayallow the inner shell 215 to withstand the operating conditions of thereactor chamber 15 while the outer shell 220 provides structural supportand/or other desirable properties to the reactor shell 11.

In one approach, at least a portion of the inner shell 215 includes thehigh melting temperature material as described above. According toanother approach, at least a portion of the inner shell 215 includes amaterial selected from the group consisting of a carbide, a nitride,titanium diboride, a sialon ceramic, zirconia, thoria, a carbon-carboncomposite, tungsten, tantalum, molybdenum, chromium, nickel and alloysthereof. By yet another approach, at least a portion of the inner shell210 includes a superalloy and by another approach includes a materialselected from the group consisting of duplex stainless steel, superduplex stainless steel, and nickel-based high-temperature low creepsuperalloy. In this regard, the inner shell 215 may be selected toprovide beneficial operating characteristics, particularly as it isexposed to the harsh operating conditions within the reactor chamber 15.

In another approach, at least a portion of the inner shell 215 includesa high thermal conductivity material as described above. According toanother approach, the inner shell 215 includes a material selected fromthe group consisting of copper, silver, aluminum, zirconium, niobium,and alloys thereof. By yet another approach, the inner shell 215includes a material selected from the group consisting of copper chrome,copper chrome zinc, copper chrome niobium, copper nickel and coppernickel tungsten. In another example, the inner shell 215 comprisesniobium-silver. In another approach the inner shell may include amaterial comprising a copper alloy that has been precipitation hardenedwith second phase compounds that alloy the retention of high thermalconductivity. In this regard, the inner shell 215 may be selected toprovide beneficial operating characteristics, particularly as it isexposed to the harsh operating conditions within the reactor chamber 15,including the high temperature thereof.

In one approach, the outer shell 220 may be formed of a differentmaterial than the inner shell 215. The outer shell 220 may be selectedto provide structural support or other desirable properties to thereactor shell 11. In one example, the outer shell 220 includes corrosionresistant steel. Other suitable materials for forming the outer layer205 of the reactor shell 11 include, but are not limited to, duplexstainless steel, super duplex stainless steel, and nickel-basedhigh-temperature low creep superalloy, Nimonic™ nickel-basedhigh-temperature low creep superalloy, Inco™ 718, Haynes™, 230, or othernickel alloys such as Mar-M-247.

By one approach, one or both of the inner shell 215 and the outer shell220 is formed as a casting as described previously.

In one approach, the outer shell 220 includes a tube sheet 230 asillustrated in FIG. 5. According to this approach, at least oneadditional inner shell 235 is positioned inside the outer shell 230defining a second reactor chamber 240. In this manner, a plurality ofpyrolysis reactions may occur within the plurality of reactor chambers240. By this approach, each of the inner shells 235 may include some orall of the components described above with regard to supersonic reactor5 illustrated in FIG. 1, or some components of the separate inner shells235 may be integrated. In one approach, some the inner reactor shells235 may be orientated in opposite directions. In this regard, any thrustthat may be generated by the high speed streams flowing through theinner shells will be offset by oppositely facing inner reactor shells235.

In one approach, the inner shell 215 is spaced from the outer shell 220to provide a channel 245 therebetween as illustrated in FIG. 4. In thisapproach, the channel 245 may include a pressure zone. The pressure zoneis pressurized to maintain the pressure therein at about the samepressure as the reactor chamber 15 pressure. In this regard, the innershell 215 may be configured such that it does not have to withstand ahigh pressure differential between its inner surface 250 and outersurface 255. The inner shell 215 may then be formed of a material havinga relatively lower pressure rating and/or having a relatively thin wallthickness. The outer shell 220 may then provide structural support aswell as serving as a pressure vessel to withstand the pressuredifferential between the pressure zone 245 and the outside of the outershell 220. In another approach (not shown), the inner shell 215 may abutthe outer shell 220.

In one approach, channel 245 further houses one or more sensors 216. Thesensors may detect or measure a variable such as one or more parametersor materials within channel 245. Examples of sensors include pressuresensors, temperature sensors, chemical sensors such as gas sensors,hydrogen sensors, hydrocarbon sensors, methane sensors, and others. Thesensors may be electronically connected to one or more display,monitoring and or control systems. In one approach channel 245 furtherhouses one or more support structures 217 to support inner shell 215relative to outer shell 220.

According to another approach, as illustrated in FIG. 6, a liner 260 maybe provided inside at least a portion of the reactor shell 11 to resistdeterioration of the reactor shell 11 portion due to operatingconditions within the reactor chamber 15. The liner 260 may extend alongan internal surface of the reactor shell 11 and may abut the reactorshell 11 or be spaced therefrom.

In one approach, a liner 260 includes a disposable liner. The disposableliner may comprise carbon in the form of carbon/carbon composite,pyrolytic carbon, glassy carbon, or other forms of carbon or a hightemperature alloy and may be removed and replaced after deterioration ofthe liner 260 has occurred. In this regard, the disposable liner mayprotect the reactor shell from the harsh operating conditions within thereactor chamber 15.

According to another approach, the liner 260 includes aself-regenerating liner, and is able to regenerate during operation ofthe supersonic reactor 5 and/or when the supersonic reactor 5 is takenoffline. In one approach, the self-regenerating liner includes carbonthat is catalyzed to promote carbon or coke formation along the internalsurface of the reactor shell 11 to regenerate the carbon liner. Inanother approach, the self regenerating liner includes aself-regenerating lining having a graphitic layer of coke. In anotherapproach, the self-regenerating liner includes a lining having ananostructured layer of coke. In yet another approach, theself-regenerating liner includes a lining with a nanostructured layer ofgraphene. In one approach, the self-regenerating liner includesdirectional thermal conductivity too quickly remove heat from thereaction chamber 15 during operation.

In one approach, the liner 260 includes a low thermal conductivitycoating which operates to provide protection for the metal alloys used,and slow down heat transfer. In another approach, the liner may be afloating captured liner made from high temperature resistance, lowthermal conductivity materials. Such a liner would reduce heat transferand erosion. A floating captured liner may be formed by vacuum plasmaspray of an HfC or rhenium onto a suitable mandrel machined to the netshape dimensions of the required liner outer diameter. The spray coatingof the HfC or rhenium would be followed by a tungsten structural layercapable of supporting the structure at the necessary temperatures. Thetungsten layer would be followed by molybdenum and possibly anothertungsten and or a nickel, cobalt, chromium, aluminum yttrium structurallayer. All layers would be applied using vacuum plasma spray and willstand alone after the inner diameter of the mandrel is chemicallyetched.

In one approach, one or more portions of the reactor shell 11 includeactive cooling to dissipate heat from the reactor chamber 15 andrestrict melting or other deterioration of the reactor shell 11 due tohigh temperatures and other operating conditions. In one approach, theactive cooling includes an active cooling system. As illustrated in FIG.7, a cross-section of a portion of the reactor shell 11 is illustratedshowing an active cooling system that includes a plurality of coolingpassageways 300 formed in the reactor shell 11 to flow a coolant alongthe reactor shell 11 to remove heat therefrom. The active cooling systemmay also include a coolant source for providing pressurized coolantpassing through the cooling passageways 300. As illustrated in FIG. 7,the cooling passageways may extend generally circumferentially about thereactor shell 11, which in one approach includes a generally annularconfiguration. Manifold tubes may also be present for providing coolantto and from the cooling passageways 300.

In one approach, the cooling passageways 300 may include one or aplurality of channels formed in a surface of the reactor shell. Inanother approach, the cooling passageways 300 may include one or aplurality of tubes or generally hollow tunnels formed in the reactorshell 11 for flowing the cooling fluid therethrough, as in theillustrated form in FIG. 7. The passageways 300 may extend along one ormore surfaces of the reactor or they may be formed within the walls ofthe reactor shell 11 as illustrated in FIG. 9. The passageways 300 maybe provided in a variety of orientations and may extend axially alongthe reactor shell 11, circumferentially about the reactor shell 11,radially through the reactor shell, helically about the annular reactorshell or other orientations known in the art.

In yet another approach, the cooling passageways 300 may include one ormore spaces between inner and outer layers, linings, or inner and outershells, as described previously, to provide one or more coolingchannels, such as in channel 245 of FIG. 4. In addition, a flowmanipulator may be provided within the space between inner and outerlayers, linings or shells to direct cooling fluid along a desired flowpattern. As illustrated in FIG. 10, protrusions 315, such as pins, fins,or other protrusions, may be used within the space between inner andouter layers to increase surface area for cooling. Further, the coolingsystem may include a combination of different types of coolingpassageways 300 as described herein. For example, the coolingpassageways 300 may include a cooling channel 300 between layers 215 and220 of a reactor shell 11 along with channels formed in a surface of oneof the inner layer 215 and outer layer 220 such that coolant flowingthrough the cooling channels also passes through the reactor shellchannels 245.

Cooling passageways 300 may be formed by a variety of methods. In oneapproach, cooling passageways 300 are machined into the reactor shell.In another approach, partial passageways may be formed along surface(s)of one or more layers, or shells, of a reactor shell 11 as describedabove, and a complete passageways 300 may be formed between the layersor shells upon joining the layers and and/or shells together as shown inFIG. 10. Similarly, a partial passageway may be formed on a surface of areactor wall or layer and a coating or liner may be applied over thepartial passageway to provide a complete passageway 300 between thereactor wall or layer and the coating or liner. In yet another approach,a coating or liner may be applied in a pattern defining a complete orpartial passageway. Such partial or complete passageways may be formedas described above by machining, casting, or during application of aparticular coating, layer or liner, or by other means. Coolingpassageways 300 may also be formed by other methods as is generallyknown in the art. Pins, fins, or other protrusions may be used withinthe passageways to increase surface area for cooling. A low thermalconductivity coating may be applied to a liner, the coating operating toprovide protection for the metal alloys used, and slow down heattransfer to the active cooling and increasing efficiency. By way ofexample, the coating may be a nickel or copper alloy that is vacuumplasma sprayed onto the inner lining first starting with a bond coatingwhich allows adhesion of the structural metal to the low thermalconductivity material. The bond coating may contain nickel, chromium,cobalt, aluminum, and or yttrium, followed by molybdenum and tungsten,and finally followed by HfC or HfO2.

The walls that define the cooling passageways may aid in heat transferinto the circulated coolant by serving as cooling fins and also supportcoolant pressure loads. In one approach, the thickness of the hot gaswall (the portion of the reactor shell 11 wall between the coolant andthe hot combustion gas) is optimized to minimize the resistance to heatflow through the walls of the liners and into the coolant channels 300while providing structural integrity relative to the pressure andthermal loads. In one approach, the thickness of the hot gas wall isbetween about 0.10 inch and about 0.375 inch, and in another example isbetween about 0.15 inch and about 0.225 inch. In another approach thewalls between cooling passages are optimized as fins to provide lowthermal resistance from the hot wall to the coolant as well as maintainstructural integrity.

In another approach, the coolant passages contain flow enhancers toenhance the flow of coolant to increase the coolant heat transfercoefficient and heat flux from the wall to the coolant. In one approach,the flow enhancers contain ribs oriented perpendicular or at a lesserangle to the coolant flow direction to re-start the coolant boundarylayer, increasing the coolant heat transfer coefficient and increasingheat flux from the wall into the coolant. Swirl imparted by ribspositioned at an angle less than 90 degrees will impart a swirl velocitycomponent, mixing the coolant and causing a higher heat transfer ratefrom the wall to the coolant.

When the reactor shell 11 is assembled, the manifold tubes and thenetwork of coolant channels 300 cooperate to form a manifold for theflowing coolant to remove the heat generated during the combustionprocess in the supersonic reactor 5 to the extent needed to maintain anacceptable reactor wall temperature.

In one approach, the cooling fluid is pressurized to a relatively highpressure such that coolant flowing through portion of the reactor shell11 has a pressure of between about 350 psig and about 3200 psig, and inanother approach between about 1000 psig and about 2000 psig. And inanother approach between about 1500 and about 1600 psig. The relativelyhigh pressure reduces the complexity of the coolant circulation byavoiding a phase change when using, for example, water as the coolingfluid. The coolant pressure, circulation rate, and temperature are setto provide sufficient coolant flow to sufficiently remove a portion ofthe heat generated in the reactor chamber 15 to maintain an acceptablereactor wall temperature, particularly during combustion of the fuelstream and supersonic expansion. In one approach, the coolant has aflowrate through the coolant passageways of between about 28,000 pph andabout 47,000 pph, and in another example between about 33,500 pph andabout 80,000 pph. In one example, coolant has an inlet temperature ofbetween about 50° F. to about 250° F. and in another example betweenabout 85° F. to about 150° F. In one example, coolant has an outlettemperature of about 100° F. to about 700° F. and in another example,from about 250° F. to about 600° F. A variety of coolants known in theart may be used. In one example, the coolant includes water. In anotherexample the coolant includes, steam, hydrogen or methane, and maycontain a mixture of fluids.

In one approach, impingement cooling may be employed as the activecooling to dissipate heat from the reactor chamber 15 and restrictmelting or other deterioration of the reactor shell 11 due to hightemperatures and other operating conditions. Impingement cooling mayemploy a gas or a liquid. In one approach the impingement cooling mayemploy a series of impingement jets to affect high heat transfer. Forexample, a high velocity jets may be directed onto a shell to be cooled.As the cooling jet contacts the surface of the shell it is diverted inall directions parallel to the shell surface. The jets may be arrangedabout the shell, such as randomly or in a pattern. Impingement coolingmay include techniques such as high impingement systems using vaporexpansion for hot wall cooling, liquid wall impingement, and gaseffusion cooling.

In one approach, a heat pipe may serve as the active cooling mechanism.Heat pipes can conduct up to 250 times the thermal energy of a solidcopper conducting member.

In one approach, as illustrated in FIG. 12, a film barrier 350 may beprovided along an inner surface of at least a portion of the reactorshell 11 to provide at least a partial barrier to the reactor chamber15. The film barrier 350 may assist in restricting deterioration,including melting, erosion, or corrosion, of the reactor shell 11 due tothe high temperatures, flowrates, and other harsh conditions within thereactor chamber 15.

In one approach, the film barrier 350 includes a cold fluid barrier. Asused herein, cold fluid barrier refers to the temperature of the fluidbarrier relative to the temperature in the reactor chamber 15. Thus, thecold fluid barrier may have a high temperature, but be cool relative tothe rector chamber 15. In one example, the temperature of the cold fluidbarrier is between about 3000° F. and about 5000° F. In another example,the temperature of the cold fluid barrier is between about 3600° andabout 4600° F.

The cold fluid barrier may include a cold vapor barrier by one example.In another example, the cold fluid barrier includes a molten metalbarrier. In another example, the cold fluid barrier includes water orsteam. In another approach, the cold fluid barrier includes air orhydrogen. In yet another example, the cold fluid barrier includesmethane. The cold fluid barrier may also include other fluids as knownin the art or a combination of fluids. By one approach, the cold fluidbarrier includes a fluid that comprises at least a portion of theprocess stream.

The film barrier may be provided over the internal surface of theportion of the reactor shell 11 in various manners. Referring to FIG.13, in one approach, the reactor shell 11 includes openings 360 throughat least a portion thereof to allow cold fluid to pass therethrough andform a cold fluid barrier. This may take the form of slots thatdischarge into the core flow. In another approach, the reactor shell 11may include a porous wall 365 that facilitates cold fluid leakingtherethrough to provide the fluid barrier. By one approach, the reactorshell may include passageways (not shown) similar to those describedabove with regard to the active cooling system and a cold fluid forforming the cold fluid barrier may be provided therethrough. In thisapproach, manifold tubing may be provided to introduce the cold fluidthrough the passageways and openings. In another approach, the reactorshell 11 may include an inner shell 215 and an outer shell 220 asdescribed previously, and the inner shell 215 may include openings orcomprise a porous wall over at least a portion of the inner shell 215.In this approach, cold fluid may be passed through the channel orpassageways defined between the outer shell 220 and the inner shell 215so that leaks through the porous wall inner shell 215 to form the coldfluid barrier over an inner surface of the portion of the inner shell215. Likewise, where a liner 260 is provided inside of the reactor shell11, as described above with regard to FIG. 6, the liner may be a porousor penetratable liner to allow cold fluid to pass through the liner andform a cold fluid barrier on an inner surface thereof. The film barriermay also be formed along the inner surface of the portion of the reactorshell 11 by other methods, including those known in the art.

In another approach, the wall may contain a plethora of small holes 360that discharge the fluid in a film, forming a full coverage film cooledsurface.

In another approach, the wall may contain slots or louvers which aresupplied with coolant and form a cooling film by discharging the coolantalong the wall in a downstream direction. The film barrier 350 may alsobe formed along the inner surface of the portion of the reactor shell 11by other methods, including those known in the art.

In another approach, the impingement method maybe combined with the fullcoverage film cooling method, wherein the impingement fluid afterimpacting the hot wall is discharged through the film cooling holes 360in such wall 365 providing two cooling effects.

In this manner, by providing a film barrier 350 over an inner surface ofat least a portion of the reactor shell 11, deterioration of the reactorshell 11 may be restricted during operation of the supersonic reactor 5.The film barrier may reduce the temperature that the reactor shell 11 isexposed to during operation by providing a barrier to the hot core fluidand convectively cooling the wall with the film at the film coolingtemperature.

The cooling system may incorporate various mechanisms as described aboveto provide the optimum combination for highest operating efficiency.

The foregoing description provides several approaches with regard to areactor shell 11 or a portion of a reactor shell 11. In this manner, itshould be understood that at least a portion of the reactor shell 11 mayrefer to the entire reactor shell 11 or it may refer to less than theentire reactor shell as will now be described in further detail. Assuch, the preceding description for ways to improve the constructionand/or operation of at least a portion of the reactor shell 11 may applygenerally to any portion of the reactor shell and/or may apply to thefollowing specifically described portions of the reactor shell.

It has been identified that certain portions or components of thereactor shell 11 may encounter particularly harsh operation conditionsor specific problems that are peculiar to that portion or component.Thus, according to various approaches, certain aspects of the precedingdescription may apply only to those portions or components were aparticular problem has been identified. Locations around fuelinjector(s) 30 and feedstock injector(s) 45 are examples of locationsthat may benefit from local film barriers or film cooling or impingementor locally positioned convective cooling passages.

One zone of the supersonic reactor 5 that encounters particularly harshoperating conditions during operation thereof is the combustion zone 25.In the combustion zone 25 the fuel stream is combusted in the presenceof oxygen to create the high temperature carrier stream. Temperatures inthe combustion zone 25 may be the highest temperatures present in thereactor chamber 15, and may reach temperatures of between about 2000°and about 3500° C. in one example, and between about 2000° and about3200° C. in another example. Thus a particular problem that has beenidentified in the combustion zone 25 is melting of the reactor shell 11at the combustion zone 25 and oxidation of the combustor walls with thepresence of oxygen. The portion of the reactor shell in a combustionzone 25 may be referred to as the combustion chamber 26.

Another zone of the supersonic reactor 5 that encounters particularlyharsh operating conditions includes the supersonic expansion zone 60,and particularly the supersonic expander nozzle 50 located therein.Specifically, due to the high temperature carrier gas traveling at nearsupersonic or supersonic speeds through the expander nozzle 50, theexpander nozzle 50 and/or other portions of the supersonic expansionzone 60 may be particularly susceptible to erosion.

Similarly, other portions of the supersonic reactor including a diffuserzone 60, a mixing zone 55, the reactor zone 65, and the quench zone mayencounter harsh operating conditions during operation of the supersonicreactor 5. Additional equipment or components that are used inconjunction with the supersonic reactor 5 may also face similar problemsand harsh operation conditions, including, but not limited to, nozzles,lines, mixers, and exchangers.

Due to unique problems and operating conditions to which individualportions or components of the supersonic reactor may be exposed, theseindividual portions or components may be formed, operated, or used inaccordance with the various approaches described herein, while otherportions or components are formed, operated, or used in accordance withother approaches, that may or may not be described herein.

Because different components or portions of the supersonic reactor 5 maybe formed or operate differently, the supersonic reactor 5, includingthe reactor shell 11, may be made as separate parts and assembled toform the supersonic reactor 5 or the reactor shell 11. In this regard,the supersonic reactor 5 and/or the reactor shell 11 may include amodular configuration wherein individual modules or components 400 canbe assembled together as shown in FIG. 11. By one approach at least someportions or components 400 of the assembled a supersonic reactor orreactor shell 11 may not be attached, instead the gases or fluidstherein may be contained by differential pressure adjustment betweencomponents. In other approaches, the modules or components 400 may beconnected together for example by flanges 405 sealed at cooled locationsof the interface between the components. Similarly, differentcomponents, portions, or modules 400 may include different aspectsprovided in the description above. For example, some modules orcomponents 400 may include active cooling, a film barrier, inner andouter layers, inner and outer shells, or other aspects described above,while other portions, modules, or components 400 may include differentaspects.

According to one approach, one or more components or modules 400 may beremoved and replaced during operation of the supersonic reactor 5 orduring downtime thereof.

For example, because the supersonic expansion nozzle 50 may deterioratemore quickly than other components of the reactor, the nozzle 50 may beremovable so that it can be replaced with a new nozzle upondeterioration thereof. In one approach, the plurality of supersonicreactors 5 may be provided in parallel or in series with one or moresupersonic reactors in operation and one or more supersonic reactors instandby so that if maintenance or replacement of one or more componentsof the operating supersonic reactor 5 is required, the process may beswitched to the standby supersonic reactor to continue operation.

Further, the supersonic reactors may be oriented horizontally asillustrated in FIG. 1, or vertically (not shown). Where the reactor isconfigured vertically, the flow of the carrier and feed streamstherethrough may be vertically up in one approach. The flow of thecarrier and feed streams may be vertically down in another approach. Inone approach the supersonic reactor may be oriented such that it is freedraining to prevent the accumulation of liquid in the quench zone 72. Inanother approach the reactor may be oriented vertically (90° fromhorizontal) or horizontally (0° from horizontal) as indicated above ormay be oriented at an angle between 0° and 90° with the reactor inlet atan elevation above the reactor outlet. In another embodiment the outlet80 may include two or more outlets, including a primary outlet 80 forthe main vapor phase flow and a secondary outlet 81 to drain liquid. Inone approach liquid is injected to quench zone 72 and is not fullyvaporized. This may occur during transient or steady state mode ofoperation. The secondary outlet may be operated continuously orintermittently as needed.

In one approach, the reactor shell 11 is sealed at one end and includesa plenum at an end opposite thereof.

By one approach, the reactor shell 11 may include a pressure reliefdevice 218 as illustrated in FIG. 4. In one approach, the pressurerelief device 218 includes a rupture disc. In another approach, thepressure relief device 218 includes a relief valve.

In one approach, as shown in FIG. 14, the supersonic reactor 5 mayinclude an isolation valve 450 at an inlet thereof. The supersonicreactor may also include a control system 455 to detect a change inpressure in the event of a blowout. The control system 455 may beconfigured to isolate the inlet in response thereto. In one approach,the inlet is a fuel stream 4 inlet.

According to one approach, the supersonic reactor 5 includes magneticcontainment to contain reactants within the reaction chamber 15.

According to another approach, the supersonic reactor 5 may includehydrogen generation to generate hydrogen from the reactor effluentstream.

In one example, the reactor effluent stream after pyrolysis in thesupersonic reactor 5 has a reduced methane content relative to themethane feed stream ranging from about 15 mol-% to about 95 mol-%. Inanother example, the concentration of methane ranges from about 40 mol-%to about 90 mol-% and from about 45 mol-% to about 85 mol-% in anotherexample.

In one example the yield of acetylene produced from methane in the feedin the supersonic reactor is between about 40% and about 95%. In anotherexample, the yield of acetylene produced from methane in the feed streamis between about 50% and about 90%. Advantageously, this provides abetter yield than the estimated 40% yield achieved from previous, moretraditional, pyrolysis approaches.

By one approach, the reactor effluent stream is reacted to form anotherhydrocarbon compound. In this regard, the reactor effluent portion ofthe hydrocarbon stream may be passed from the reactor outlet to adownstream hydrocarbon conversion process for further processing of thestream. While it should be understood that the reactor effluent streammay undergo several intermediate process steps, such as, for example,water removal, adsorption, and/or absorption to provide a concentratedacetylene stream, these intermediate steps will not be described indetail herein.

Referring to FIG. 2, the reactor effluent stream having a higherconcentration of acetylene may be passed to a downstream hydrocarbonconversion zone 100 where the acetylene may be converted to form anotherhydrocarbon product. The hydrocarbon conversion zone 100 may include ahydrocarbon conversion reactor 105 for converting the acetylene toanother hydrocarbon product. While FIG. 2 illustrates a process flowdiagram for converting at least a portion of the acetylene in theeffluent stream to ethylene through hydrogenation in hydrogenationreactor 110, it should be understood that the hydrocarbon conversionzone 100 may include a variety of other hydrocarbon conversion processesinstead of or in addition to a hydrogenation reactor 110, or acombination of hydrocarbon conversion processes. Similarly, unitoperations illustrated in FIG. 2 may be modified or removed and areshown for illustrative purposes and not intended to be limiting of theprocesses and systems described herein. Specifically, it has beenidentified that several other hydrocarbon conversion processes, otherthan those disclosed in previous approaches, may be positioneddownstream of the supersonic reactor 5, including processes to convertthe acetylene into other hydrocarbons, including, but not limited to:alkenes, alkanes, methane, acrolein, acrylic acid, acrylates,acrylamide, aldehydes, polyacetylides, benzene, toluene, styrene,aniline, cyclohexanone, caprolactam, propylene, butadiene, butyne diol,butandiol, C2-C4 hydrocarbon compounds, ethylene glycol, diesel fuel,diacids, diols, pyrrolidines, and pyrrolidones.

A contaminant removal zone 120 for removing one or more contaminantsfrom the hydrocarbon or process stream may be located at variouspositions along the hydrocarbon or process stream depending on theimpact of the particular contaminant on the product or process and thereason for the contaminants removal, as described further below. Forexample, particular contaminants have been identified to interfere withthe operation of the supersonic flow reactor 5 and/or to foul componentsin the supersonic flow reactor 5. Thus, according to one approach, acontaminant removal zone is positioned upstream of the supersonic flowreactor in order to remove these contaminants from the methane feedstream prior to introducing the stream into the supersonic reactor.Other contaminants have been identified to interfere with a downstreamprocessing step or hydrocarbon conversion process, in which case thecontaminant removal zone may be positioned upstream of the supersonicreactor or between the supersonic reactor and the particular downstreamprocessing step at issue. Still other contaminants have been identifiedthat should be removed to meet particular product specifications. Whereit is desired to remove multiple contaminants from the hydrocarbon orprocess stream, various contaminant removal zones may be positioned atdifferent locations along the hydrocarbon or process stream. In stillother approaches, a contaminant removal zone may overlap or beintegrated with another process within the system, in which case thecontaminant may be removed during another portion of the process,including, but not limited to the supersonic reactor 5 or the downstreamhydrocarbon conversion zone 100. This may be accomplished with orwithout modification to these particular zones, reactors or processes.While the contaminant removal zone 120 illustrated in FIG. 2 is shownpositioned downstream of the hydrocarbon conversion reactor 105, itshould be understood that the contaminant removal zone 120 in accordanceherewith may be positioned upstream of the supersonic flow reactor 5,between the supersonic flow reactor 5 and the hydrocarbon conversionzone 100, or downstream of the hydrocarbon conversion zone 100 asillustrated in FIG. 2 or along other streams within the process stream,such as, for example, a carrier fluid stream, a fuel stream, an oxygensource stream, or any streams used in the systems and the processesdescribed herein.

One embodiment of the present disclosure is directed to apparatus andmethods for converting methane in a hydrocarbon stream to acetyleneusing a supersonic flow reactor, while minimizing the possibility ofexplosion due to the formation of copper acetylides from a chemicalreaction between the acetylene gas generated and the copper of the innerlayer. The methane pyrolysis reactor zone presents a strong reducingenvironment in the presence of hydrogen and high temperature. Cu or CuOis found to interact readily with acetylene leading to copper acetylideformation.

A coating may be applied to an inner surface of the inner layer toprovide a barrier between the acetylene gas generated and the copper ofthe inner layer in order to prevent the formation of acetylides. Thusthe inner layer 210 may include a coating that is formed on an innersurface of the inner layer to form a barrier between the copper of theinner layer and the acetylene gas being generated. The coating can be athin coating applied to the inner surface of the inner layer of thereactor shell and can be a material that does not react with acetylene.In one embodiment, examples of suitable coatings include thosecomprising nickel metal or an alloy of nickel or a mixture thereof.Specific examples alloys of nickel include NiCrAlY, NiCoCrAlY,CoNiCrAlY, and Ni—P. With a copper containing substrate, the nickelforms a solid solution which with thermal treatment forms a very strongbond resistant to thermal shock stress. It is further envisioned thatthe nickel or alloy of nickel coating may be in addition to a thermalbarrier coating such as described above in order to slow down heattransfer. Other suitable coatings may be comprised of chromium, an alloycontaining chromium, platinum, an alloy containing platinum, palladium,an alloy containing palladium, or mixtures thereof, or mixtures of anyof the above with nickel or an alloy containing nickel.

The metal or alloy or mixture may be applied to surfaces of the reactorshell such as the inner surface of the inner layer by a variety of knownmetallization processes. Suitable examples include electroplating usingelectrical current, electroless plating which does not use electricalcurrent, or by applying using plasma spray techniques. For example, purenickel may be applied using an electroplating technique. This coatingmay not require post application thermal treatment, but adhesion can beimproved with thermal exposure from about 482° C. to about 538° C. forabout 1 to about 3 hours. The coating is dense and prevents coppercontact with acetylene gas. Furthermore, the coating may be applied incombination with, for example, a stabilized zirconia coating asdescribed earlier, in which case the dense coating provides not only abarrier to the formation of acetylide but is a heat transfer barrier aswell. In another example, the coating of an alloy of nickel, such asNiCrAlY, may be applied using plasma spray technologies. This coatingmay not require post application thermal treatment but adhesion may beimproved with thermal exposure from about 482° C. to about 538° C. forabout 1 to about 3 hours. The coating is dense and prevents coppercontact with acetylene gas. Furthermore, the coating may be applied incombination with, for example, a stabilized zirconia coating asdescribed earlier, in which case the dense coating provides not only abarrier to the formation of acetylide but is a heat transfer barrier aswell. In yet another embodiment, a Ni-P coating may be applied usingelectroless plating. As above, the coating may not require postapplication thermal treatment but adhesion may be improved with thermalexposure from about 482° C. to about 538° C. for about 1 to about 3hours. The coating is dense and prevents copper contact with acetylenegas. Furthermore, the coating may be applied in combination with, forexample, a stabilized zirconia coating as described earlier, in whichcase the dense coating provides not only a barrier to the formation ofacetylide but is a heat transfer barrier as well.

While there have been illustrated and described particular embodimentsand aspects, it will be appreciated that numerous changes andmodifications will occur to those skilled in the art, and it is intendedin the appended claims to cover all those changes and modificationswhich fall within the true spirit and scope of the present disclosureand appended claims.

1. An apparatus for producing acetylene from a feed stream comprisingmethane comprising: a supersonic reactor for receiving the methane feedstream and heating the methane feed stream to a pyrolysis temperature; areactor shell of the supersonic reactor for defining a reactor chamber;a combustion zone of the supersonic reactor for combusting a fuel sourceto provide a high temperature carrier gas passing through the reactorspace at supersonic speeds to heat and accelerate the methane feedstream to a pyrolysis temperature; an outer layer of the reactor shellfor providing structural support thereto; an inner layer of the reactorshell having a thermal conductivity of between about 200 and about 500W/m-K for conducting heat from the reactor chamber the inner layercomprising at least copper chrome, copper chrome zinc, copper chromeniobium, copper nickel and copper nickel tungsten and mixtures thereof;and a coating comprising nickel metal, an alloy of nickel, chromiummetal, an alloy of chromium, platinum metal, an alloy of platinum,palladium, or an alloy of palladium, or mixtures thereof applied to aninner surface of the inner layer of the reactor shell.
 2. The apparatusof claim 1 wherein the coating comprises NiCrAlY, or NiCoCrAlY, orCoNiCrAlY, or Ni—P, or mixtures thereof.
 3. The apparatus of claim 1wherein the coating comprises NiCrAlY.
 4. The apparatus of claim 1wherein the coating is electroplated onto the inner surface of the innerlayer.
 5. The apparatus of claim 4 wherein the coating is thermallytreated at a temperature of from about 482° C. to about 538° C. forabout 1 to about 3 hours.
 6. The apparatus of claim 4 wherein thecoating comprises nickel metal.
 7. The apparatus of claim 1 wherein thecoating is applied to the inner surface of the inner layer using plasmaspray techniques.
 8. The apparatus of claim 7 wherein the coating isthermally treated at a temperature of from about 482° C. to about 538°C. for about 1 to about 3 hours.
 9. The apparatus of claim 7 wherein thecoating comprises NiCrAlY.
 10. The apparatus of claim 1 wherein thecoating is applied to the inner surface of the inner layer using anelectroless plating process.
 11. The apparatus of claim 10 wherein thecoating is thermally treated at a temperature of from about 482° C. toabout 538° C. for about 1 to about 3 hours.
 12. The apparatus of claim10 wherein the coating comprises Ni—P.
 13. The apparatus of claim 1wherein the coating further comprises a material capable of providing athermal barrier.
 14. The apparatus of claim 1 wherein the coatingfurther comprises yttria-stabilized zirconia, lanthanum hexaluminate,rare earth-doped lanthanum hexaluminate, hafnium carbide, tungsten, ormixtures thereof
 15. The apparatus of claim 1 wherein the reactor shellis a composite having the inner and outer layers.
 16. The apparatus ofclaim 1 wherein the inner layer and outer layers comprise separatecastings and the castings are brazed together.
 17. The apparatus ofclaim 1 further comprising one or more intermediate layers between theouter layer and the inner layer.
 18. The apparatus of claim 1 furthercomprising one or more layers positioned outside of the outer layer. 19.A process for producing acetylene from a feed stream comprising methanecomprising: introducing the feed stream to a supersonic reactor whereinthe supersonic reactor comprises: a reactor shell of the supersonicreactor for defining a reactor chamber; a combustion zone of thesupersonic reactor for combusting a fuel source to provide a hightemperature carrier gas passing through the reactor space at supersonicspeeds to heat and accelerate the methane feed stream to a pyrolysistemperature; an outer layer of the reactor shell for providingstructural support thereto; an inner layer of the reactor shell having athermal conductivity of between about 200 and about 500 W/m-K forconducting heat from the reactor chamber the inner layer comprising atleast copper chrome, copper chrome zinc, copper chrome niobium, coppernickel and copper nickel tungsten and mixtures thereof; and a coatingcomprising a coating comprising nickel metal, an alloy of nickel,chromium metal, an alloy of chromium, platinum metal, an alloy ofplatinum, palladium, or an alloy of palladium, or mixtures thereofapplied to an inner surface of the inner layer of the reactor shell;combusting a fuel source to provide a high temperature carrier gaspassing through the reactor at supersonic speeds to heat and acceleratethe methane feed stream to a pyrolysis temperature, wherein upon heatingand accelerating the methane stream, acetylene is generated; andpreventing formation of acetylides in the reactor by employing thecoating that prevents the acetylene from contacting the copper of theinner layer of the reactor.